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<h3 class="section" id="Troubleshooting-the-garbage-collector"><span>23.7 Troubleshooting the garbage collector<a class="copiable-link" href="#Troubleshooting-the-garbage-collector"> &para;</a></span></h3>
<a class="index-entry-id" id="index-garbage-collector_002c-troubleshooting"></a>

<p>With the current garbage collector implementation, most issues should
show up as GCC compilation errors.  Some of the most commonly
encountered issues are described below.
</p>
<ul class="itemize mark-bullet">
<li>Gengtype does not produce allocators for a <code class="code">GTY</code>-marked type.
Gengtype checks if there is at least one possible path from GC roots to
at least one instance of each type before outputting allocators.  If
there is no such path, the <code class="code">GTY</code> markers will be ignored and no
allocators will be output.  Solve this by making sure that there exists
at least one such path.  If creating it is unfeasible or raises a &ldquo;code
smell&rdquo;, consider if you really must use GC for allocating such type.

</li><li>Link-time errors about undefined <code class="code">gt_ggc_r_foo_bar</code> and
similarly-named symbols.  Check if your <samp class="file">foo_bar</samp> source file has
<code class="code">#include &quot;gt-foo_bar.h&quot;</code> as its very last line.

</li></ul>

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